Protuberant aneurysm bridging device deployment method

ABSTRACT

A method of implanting a bridging device for supporting occlusive masses within an aneurysm located at a vascular bifurcation.

This application is continuation-in-part of U.S. application Ser. No.13/850,266 filed Mar. 25, 2013, which is a divisional application ofU.S. application Ser. No. 13/647,315 filed Oct. 8, 2012, which claimspriority to U.S. Provisional Application 61/556,122 filed Nov. 4, 2011,the entire contents of which are hereby incorporated by reference.

FIELD OF THE INVENTIONS

The inventions described below relate to the field of treatments forwide-necked aneurysms.

BACKGROUND OF THE INVENTIONS

Hemorrhagic stroke accounts for 20% of the annual stroke population.Hemorrhagic stroke often occurs due to rupture of an aneurysm, causingbleeding into the brain tissue and resultant infarction of brain tissue.This can cause immediate death, as well as several well-knownneurological defects such as paralysis, loss of sight, hearing orbalance. Even if aneurysms in the brain do not rupture, they can causesevere neurological symptoms. Aneurysms may be filled with occlusivematerial, such as embolic coils, flow modifiers, stents or embolicpolymers (ethylene vinyl alcohol, cyanoacrylate, etc.), to preventrupture and alleviate neurological symptoms. This treatment is promisingfor many aneurysm in the cerebral vasculature. However, the cerebralvasculature includes many branches and bifurcations where an inletartery branches into two outlet arteries. Large necked aneurysms(greater than 4 mm, with dome to neck ratios of greater than two) oftenform at these bifurcations, and the location and openings of theseaneurysms often make it difficult to keep occlusive material, onceplaced in the aneurysm, from falling out of the aneurysm and into thearteries, thus blocking the outlet arteries. This can lead to an embolicstroke, which is just as severe as the hemorrhagic stroke the therapy isintended to prevent.

SUMMARY OF THE INVENTIONS

The devices and methods described below provide for occlusion of a widenecked aneurysm near a vascular bifurcation or trifurcation andplacement of an occlusive material in the aneurysm while maintaining orcreating a patent flow path for blood to flow from the feeding vesselinto both branches of the bifurcation. The device comprises a vesselconforming, protuberant aneurysm bridging device, and is delivered witha delivery system capable of being deployed in the vicinity of acerebrovascular aneurysm and allow for patent arterial flow whileholding embolic material at the neck or slightly herniating into theneck of the aneurysm. The geometry and mechanics of the protuberantaneurysm bridging device are configured to cause retention of the devicewithin the vessel in which the device is placed and maintain patency ofthe vessels into which the device is placed. The device delivery systemis configured to deliver the device, through a microcatheter, with ahigh degree of accuracy under visualization by fluoroscopy, ultrasound,MRI, or the like. The device delivery system allows for the manipulationand expansion of the protuberant section of the device to conform to thevasculature.

The protuberant aneurysm bridging device is configured to be placed in aparent vessel, across an aneurysm. The aneurysm can be located within ornear a bifurcation. Bifurcation anatomies include the distal end of thebasilar artery as well as the location where the middle cerebral arterybegins, among many other examples. The protuberant aneurysm bridgingdevice can also be placed across an aneurysm that is not at abifurcation but formed into the sidewall of a generally non-bifurcatedvessel. The protuberant aneurysm bridging device is configured to becoarse enough to allow blood to pass through its open walls but tightenough to keep embolizing coils trapped within an aneurysm such thatthey cannot protrude out of the aneurysm into the parent vessel orvessels.

The protuberant aneurysm bridging device can comprise a cylindricalfirst end and a cylindrical second end. The central region of the devicecan comprise a protuberant, or generally hemispherical, configuration.The central region can comprise a greater open area than the cylindricalfirst end, the cylindrical second end, or both ends. In otherembodiments, the device can be configured with a cylindrical first endhaving a hollow lumen and be closed at the other ends. The closed otherends can comprise openings between the mesh or strut elements that arelarger in some areas than the central areas of the device.

The device can comprise a mesh. In other embodiments, the device cancomprise an expanded metal structure formed by slitting or laser-cuttinga tube to form struts, for example. The device's mesh or struts canextend slightly into the aneurysm to insure the embolic material is notcovering branching arteries.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the vasculature of the brain showingthe placement of a protuberant aneurysm bridging device.

FIG. 2 is schematic diagram of the vasculature of the brain illustratingthe circle of Willis and arteries supplying the circle of Willis, alsoshowing the placement of the protuberant aneurysm bridging device.

FIGS. 3 and 4 illustrate a protuberant aneurysm bridging device for usein bridging a bifurcation aneurysm.

FIGS. 5 and 6 illustrate a protuberant aneurysm bridging device for usein bridging a bifurcation aneurysm with a proximal region modified toprovide additional holding power in an inlet vessel.

FIG. 7 illustrates the placement of radiopaque markers in variouspositions on the bridging device.

FIG. 8 illustrates the attachment mechanism for securing the bridgingdevice to the delivery wire.

FIG. 9 a-9 g illustrate several steps of delivering the bridging deviceto the site of a bifurcation aneurysm.

FIG. 10 illustrate the bridging device fully deployed at the site of abifurcation aneurysm.

FIG. 11 illustrates the step of filling the aneurysm sac with occlusivematerial, after placement of the bridging device.

FIG. 12 illustrates a protuberant aneurysm bridging device followinginitial forming being wrapped around a construction mandrel for finalshaping.

FIG. 13 illustrates a protuberant aneurysm bridging device side viewwherein the device includes a proximal end, a distal end, and severaldistinct segments there between.

FIG. 14 illustrates one end of a protuberant aneurysm bridging devicewherein the device includes an end segment, a first intermediatesegment, a second intermediate segment, and a central segment.

FIG. 15 illustrates a complete protuberant aneurysm bridging deviceformed in the manner of the device of FIG. 14 but showing all the devicesegments.

FIG. 16 illustrates a flat pattern diagram of a protuberant aneurysmbridging device wherein the device is fabricated from a flat sheet ofmaterial and before any forming of intermediate segments.

FIG. 17 illustrates a protuberant aneurysm bridging device fabricatedfrom the flat pattern of FIG. 13 and formed around an axially elongatecylindrical shape with further forming generating different patterns inthe proximal and distal first intermediate segments as well as thecentral segment.

FIG. 18 illustrates a protuberant aneurysm bridging device fabricatedinto its cylindrical shape but having larger length second intermediatesegments and shorter length end segments.

FIG. 19 illustrates a protuberant aneurysm bridging device fabricatedinto an axially elongate cylindrical shape with shorter secondintermediate segments than the device of FIG. 18.

FIG. 20 illustrates a flat pattern of a protuberant aneurysm bridgingdevice similar to the flat pattern of FIG. 13 except that the two firstintermediate segments and the central segment are longer and morelaterally disposed than that of the flat pattern of FIG. 16.

FIG. 21 illustrates a protuberant aneurysm bridging device fabricatedfrom the flat pattern shown in FIG. 20 and formed into a cylindricalshape.

FIG. 22 illustrates a close-up of a protuberant aneurysm bridging deviceflat pattern such as that of FIG. 20 illustrating details of the bargeometry.

FIG. 23 illustrates an oblique view of a protuberant aneurysm bridgingdevice formed into a cylindrical shape and constructed from a flatpattern such as that shown in FIG. 20.

FIG. 24 illustrates an oblique view of a cylindrically formedprotuberant aneurysm bridging device with less severe bending than thatof the device in FIG. 23.

FIG. 25 a illustrates a cerebrovascular aneurysm located at a vesselbifurcation.

FIG. 25 b illustrates a cerebrovascular aneurysm located at a vesselbifurcation with a commercially available cerebrovascular stent placedacross the neck of the aneurysm.

FIG. 25 c illustrates a cerebrovascular aneurysm located at a vesselbifurcation with a protuberant aneurysm bridging device placed acrossand partially within the neck of the aneurysm.

FIG. 26 a illustrates a giant cerebrovascular aneurysm located at avessel bifurcation.

FIG. 26 b illustrates a giant cerebrovascular aneurysm with illustratesa cerebrovascular aneurysm located at a vessel bifurcation with acommercially available cerebrovascular stent placed across the neck ofthe aneurysm.

FIG. 26 c illustrates a giant cerebrovascular aneurysm with a stylizeddevice slightly herniating into the aneurysm neck and the second of twobifurcation outflow vessels.

FIG. 27 a illustrates a cerebrovascular aneurysm located at a vesselbifurcation.

FIG. 27 b illustrates a giant cerebrovascular aneurysm located at avessel bifurcation with a commercially available cerebrovascular stentplaced across the neck of the aneurysm.

FIG. 27 c illustrates a cerebrovascular aneurysm with a stylized deviceplaced across the aneurysm neck and the bifurcation inflow vessel.

FIG. 28 a illustrates a small cerebrovascular aneurysm at a trifurcationwith a stylized device slightly herniating into the aneurysm neck andtwo of the trifurcation exit vessels.

FIG. 28 b illustrates a cerebrovascular aneurysm located at a vesselbifurcation with a commercially available cerebrovascular stent placedacross the neck of the aneurysm.

FIG. 28 c illustrates a cerebrovascular aneurysm with a stylized deviceplaced across the aneurysm neck and the bifurcation inflow vessel.

DETAILED DESCRIPTION OF THE INVENTIONS

FIGS. 1 and 2 show the vasculature of the brain in sufficient detail toillustrate the use of the protuberant aneurysm bridging device shown inthe following illustrations. The bridging device 1 is shown in anexemplary placement. The bridging device is delivered to this site of avascular defect with the delivery catheter 2. The neuro-vasculature,which is the intended environment of use for the embolic implant,supplies the brain 3 with blood through the carotid and the vertebralarteries on each side of the neck. The important arteries include thecommon carotid artery 4 in the neck and the internal carotid artery 5which supplies the ophthalmic artery 6. The external carotid 7 suppliesthe maxillary artery 8, the middle meningeal artery 9, and thesuperficial temporal arteries 10 (frontal) and 11 (parietal). Thevertebral artery 12 supplies the basilar artery 13 and the cerebralarteries including the posterior cerebral artery 14 and the circle ofWillis indicated generally at 15. The siphon 12 a of the vertebralartery appears in the intra-cranial vasculature on the vertebralapproach to the Circle of Willis. Also supplied by the internal carotidartery are the anterior cerebral artery 16 and the middle cerebralartery 17, as well as the circle of Willis, including the posteriorcommunicating artery 18 and the anterior communicating artery 19. Thesiphon 5 a of the internal carotid artery 5 appears in the intra-cranialvasculature on the carotid approach into the Circle of Willis. Thesearteries typically have an internal diameter of about 1 mm to 5 mm, mostcommonly from 2-4 mm. The methods and devices described herein allowaccess to these arteries and placement of a bridging device acrossaneurysm near bifurcations of these arteries. In

FIG. 1, the insertion catheter 2 and a bridging device 1 are shownthreaded through the common carotid artery 4 and the internal carotidartery 5, which will be a common access pathway for the bridgingdevices, with the bridging device disposed within the basilar artery 13and posterior cerebral artery 14, spanning the neck of the basilar tipaneurysm 20.

FIG. 2 shows the same blood vessels in a schematic view that betterillustrates the Circle of Willis and the arteries which supply thisimportant anatomic feature. The Circle of Willis 15 is a ring ofarteries connecting the internal carotid arteries and the basilar artery(and hence the left and right vertebral arteries) to the anteriorcerebral arteries 16, middle cerebral arteries 17 and posterior cerebralarteries 14. The system provides a redundant supply of blood to thecerebral arteries. The carotid siphon 5 a, which forms an integral partof the internal carotid artery 5, is more clearly visible in this view.Aneurysms occurring inside the brain, at bifurcations in theintracranial portion of the carotid arteries, vertebral arteries (andthe portions of those arteries distal to the siphons) and basilarartery, in the Circle of Willis or even deeper within the brain may betreated with the bridging device and delivery systems described below.FIG. 2 shows an exemplary use in which a delivery catheter 2 is insertedthrough the vertebral artery to the basilar artery to treat a vasculardefect 20 (a basilar tip aneurysm, in this case) with a bridging device.

FIGS. 3 and 4 illustrates a protuberant bridging device for use inbridging a bifurcation aneurysm. The bridging device 1 comprises astent-like wire-frame structure, substantially tubular in out-line butwith most of its wall material removed. The bridging device is highlyflexible, compressible and expandable longitudinally, and compressibleand expandable radially, and can be manipulated within the vasculatureto shape it to obtain a bulbous center while fixing the ends to segmentsof blood vessel bifurcation on either side of a bifurcation aneurysm.The bridging device is characterized by a distal region 21 and aproximal region 22 and a central region 23. The distal region serves asan anchoring portion, to secure the distal end of the device in a firstoutlet vessel. The proximal region serves as an anchoring portion, tosecure the proximal end of the device in the inlet vessel. The centralregion serves as a bridging region and a scaffold, to bridge the neck ofthe aneurysm and hold embolic material in the aneurysm and maintainpatency of a second outflow vessel.

The distal region, which corresponds to the distal end of the device(distal referring to the region intended to be disposed deepest withinthe vasculature (farthest for the origin of an artery), which generallycorresponds to the end of the device farthest from the delivery catheteror insertion point in the body) comprises two zigzag segments 24 and 25disposed with opposing vertices 26 and 27 aligned (the two opposingzigzag segments form a diamond-cell segment 28, characterized by diamondshaped opening between defined by the struts of opposing V-shaped pairsof struts). The zigzag segments are superelastically or resilientlybiased to open to the generally cylindrical configuration shown in orderto expand to engage the walls artery in which it is place withsufficient compliance mismatch to fix the distal region within theartery.

The proximal region, which corresponds to the proximal end of the device(proximal referring to the region intended to be disposed closest to theorigin of an artery, which generally corresponds to the end of thedevice closest to the delivery catheter or insertion point in the body)comprises a zigzag segment 29 and several V-shaped elements 30 disposedwith tops 31 aligned with proximally pointing vertices 32 (formingspaced, non-contiguous diamond-cell segments 33, characterized bydiamond-shaped opening defined by the struts of opposing V-shaped pairsof struts). The zigzag segments are superelastically or resilientlybiased to open to the generally cylindrical configuration shown in orderto expand to engage the walls of the artery in which it is placed withsufficient compliance mismatch to fix the proximal region within theartery. The distal region and proximal region establish a cylindricalstructure with dimensions, in their expanded configurations, that matchor slightly exceed the diameter of the blood vessel in which they are tobe placed. Though V-shaped elements are preferred (for both the distalregion and proximal region), the zigzag segments can be configuredinstead as sinusoidal or wavy segments, with U-shaped elements, for usein larger environments.

The central region 23 is intended to be bulbous, and protrude radiallyfrom the cylinder established by the distal end and proximal end, in itsexpanded configuration. The central region comprises a pair of opposingzigzag segments 34 and 35 with the vertices aligned to meet near thecenter of the device, again forming a diamond-cell segment 36 (that is,the centrally pointing vertices of the first central zigzag segment 34are aligned with centrally pointing vertices of the second centralzigzag segment 35). This paired zigzag or diamond cell segment isjoined, on its proximal end, to the distal end of proximal region. Theproximally pointing vertices 37 are connected to the distally pointingvertices 38 of zigzag segment 29 with spirally oriented strut segments39 which run, along a helical or spiral course relative to the cylinderestablished by the distal and proximal regions, from the distallypointing vertices 38 to the proximally pointing vertices 37. Likewise,the paired zigzag or diamond cell segment 36 is joined, on its distalend, to the proximal end of distal region. The distally pointingvertices 40 are connected to the proximally pointing vertices 41 ofzigzag segment 29 with spirally oriented strut segments 42 which run,along a helical or spiral course relative to the cylinder established bythe distal and proximal regions, from the distally pointing vertices 40to the proximally pointing vertices 41. The zigzag segments and spiralstruts are superelastically or resiliently biased to open to thegenerally cylindrical configuration shown (larger diameter than thedistal region and proximal region) in order to expand to engage both thewalls of the artery in which it is placed and bridge the open neck ofthe aneurysm. The spirally oriented struts provide a hinged connectionbetween the central region and both the proximal region and distalregion. Because the central region is intended to bulge and protrudefrom the central axis of the device, it is preferably devoid ofadditional structures, beyond the spiral struts, zigzag segments andmarkers, so that it is not constricted from deforming duringinstallation according to the procedure described below.

At the proximal end of the bridging device, the device is removablyattached to the delivery wire 43 through an electrolytic detachmentjoint 44 and several tethers 45. The tethers are additional struts,formed integrally with the remainder of the device, extending around thecylindrical volume established by the proximal region segments, to jointhe detachment joint along the side of the device. The delivery wireruns through insertion catheter 2.

The bridging device is collapsible to a small diameter configurationwhich fits inside the distal end of the delivery catheter, and can passthrough the lumen of the delivery catheter, for insertion into the body,navigation through the patient's vasculature, and deployment from thedistal end. The bridging device, as illustrated, is in its expanded,large diameter configuration, which it assumes after ejection from thedistal end of the delivery catheter.

The bridging device includes several radiopaque markers 46 disposed onthe distal region. As illustrated, the distal markers are disposed onthe distally pointing vertices of the distal-most zigzag segment of thedevice. Three markers are provided at this longitudinal location, thedistal vertices of the distal zigzag segment 24. An additional marker 47is disposed on a spiral strut near the distal region, marking theproximal extent of the distal region. Several radiopaque markers 48 aredisposed at the central vertices of the central paired zigzag segment(in this embodiment, each central vertex is marked with its own marker).Also, a radiopaque marker 49 is disposed near the proximal region, on aspiral strut, marking the distal extent of the proximal region. Asillustrated, the proximal marker is disposed on a spiral strut justdistal to a distally pointing vertex of the proximal-most zigzag segmentof the device. The radiopaque markers facilitate the method of placingthe device, which is described below.

FIG. 4 is a schematic illustration of the bridging device of FIG. 3,showing the device as it would appear if opened and splayed out on aflat surface. FIG. 4 shows all the same detail of FIG. 3, and providesan additional view of the zigzag segments, the spiral struts, and thetethers. As can be seen in this Figure, the spiral struts 39 connect aproximally pointing vertices 41 of the distal zigzag segment 25 with adistally pointing vertices 40 of the central region which iscircumferentially displaced by at least two other vertices.

As appears from FIGS. 3 and 4 the first central zigzag segment 34 (whichopposes the distal region) is characterized by distally pointingvertices, and the second central zigzag segment 35 (which opposes theproximal region) is characterized by proximally pointing vertices. Thedistally pointing vertices of the first central zigzag segment arejoined by the spirally oriented struts 42 extending from an originatingdistally pointing vertex of the first central zigzag segment to a vertexof the distal zigzag segment 25 which is circumferentially displacedfrom the originating vertex. Likewise, the proximally pointing verticesof the second central zigzag segment 35 are joined by a spirallyoriented strut extending from an originating proximally pointing vertexof the second central zigzag segment to a vertex of the proximal zigzagsegment 29 which is circumferentially displaced from the originatingvertex. The displacement may be one, two or three vertices or more(using a vertex of the zigzag segments as a unit of measure around thecircumference of the device).

FIGS. 5 and 6 illustrate a protuberant aneurysm bridging device for usein bridging a bifurcation aneurysm with a proximal region modified toprovide additional holding power in an inlet vessel. This device ismodified, vis-à-vis the device shown in FIGS. 3 and 4, with the additionof another zigzag segment 50 in the proximal region. The V-segments ofthis additional zigzag segment are aligned with the V-segments of thezigzag segment 29, with the distally pointing vertices 51 of zigzagsegment 50 aligned with the proximally pointing vertices 52 of thezigzag segment 29. These opposing zigzag segments form a diamond celledsegment, which is longer than the corresponding single zigzag segment ofFIGS. 3 and 4, and provides additional holding power within the inletvessel when implanted at a bifurcation. The other elements of bridgingdevice of FIGS. 5 and 6 may be identical to the corresponding elementsshown in FIGS. 3 and 4.

FIG. 7 illustrates the placement of radiopaque markers in variouspositions on the bridging device. The markers 46 comprise any radiopaquematerial, disposed around a small portion of the wire frame structure inthe vicinity of the extreme distal tip of the V-shaped elements of thezigzag segment 24. Similar markers are placed at the center region, atthe joint between vertices 31 and 32 of the paired zigzag segments 34and 35, and also at the proximal regions at the distal vertices of theV-shaped elements of the zigzag segment 29.

FIG. 8 illustrates the attachment mechanism for securing the bridgingdevice to the delivery wire. The attachment mechanism comprises a detentball 53 at the distal end of the delivery wire 43 and detent receiver 54at the proximal end of the tether 45. To attach the bridging device tothe delivery wire, the detent ball is forced into the detent receiver.The joint is covered with a radiopaque marker 55. To detach the bridgingdevice from the delivery wire, the electrolytic detachment joint 44 issevered electrolytically, upon application of electrical current to thejoint through the delivery wire or associated conductor. Mechanicaldetachment mechanisms, including screw-thread detachment mechanisms, maybe used in place of the electrolytic detachment joint.

FIG. 9 a-9 g illustrate several steps of delivering the bridging deviceto the site of a bifurcation aneurysm. The method of treatingbifurcations aneurysms is illustrated in these Figures in the basilartip aneurysm because this is a common wide-necked aneurysm that can betreated with the bridging device. FIG. 9 a-9 g are set in the Circle ofWillis 15, treating a wide-necked aneurysm 20 at the point where thebasilar artery 13 divides into the left and right posterior cerebralarteries 18. The procedure will be performed by a surgeon, undervisualization with fluoroscopy.

As shown in FIG. 9 a, the surgeon has inserted the delivery catheter 2,with the delivery wire disposed within the catheter, and the bridgingdevice mounted on the distal tip of the delivery wire, through thepatient's vasculature so that the distal tip of the catheter 2 isdisposed within the posterior cerebral artery 14. With the catheter tipin the posterior cerebral artery 14, the surgeon pulls the deliverycatheter proximally, while holding the bridging device distally,partially deploying it from the delivery catheter so that the distalregion is outside the catheter and free to expand (superelastically orelastically, depending on the material comprising the device). Uponexpansion, the distal region of the bridging device engages the innerwall of the posterior cerebral artery. The release of the distal regionfrom the insertion catheter is seen under fluoroscopy. The struts andwires of the device will likely not be visible under current fluoroscopysystems, so the surgeon will rely on the radiopaque markers. In thisfirst step, the distal set of markers 46 appears outside the deliverycatheter, confirming that the distal region is deployed.

As shown in FIG. 9 b, the surgeon has withdrawn the insertion catheter 2to release the region of the device bearing the radiopaque marker 47,which marks the proximal extent of the distal segment. The surgeon willdeploy the device, pulling the device proximally or pushing it distally,to align this distal “edge” marker with the edge of the distal (farthestfrom the catheter tip) margin of the neck of the aneurysm, at this pointor later in the method.

As shown in FIG. 9 c, the surgeon has further withdrawn the insertioncatheter 2 to release the central region, so that region of the devicebearing the radiopaque markers 48 is deployed, and the markers appear onthe fluoroscope. All six of the central region radiopaque markers shouldbe visible. The single edge marker is still visible near the distalmargin, and the distal markers 46 are visible deeper in the posteriorcerebral artery, confirming that the distal region 21 is still properlylocated.

As shown in FIG. 9 d, the surgeon has withdrawn the delivery catheter 2to fully release the central region, so that the proximal radiopaquemarker 49 appears on the fluoroscope. The surgeon will manipulate thedevice, pushing proximally and/or pulling distally, to align this distal“edge” marker with the edge of the proximal (nearest to the cathetertip) margin of the neck of the aneurysm, at this point or later in themethod.

As shown in FIG. 9 e, the surgeon has pushed the delivery wire 43distally, maintaining the delivery catheter 2 in position, to fullyrelease the central region, to push the proximal region distally towardthe bifurcation. This results in expansion of the central region, andspreading of the individual spiral struts and zigzag segments throughthe bifurcation, urging at least one or two of the struts or V-shapedelements into apposition with the aneurysm neck. This is indicated bythe movement of the radiopaque markers toward the neck, as illustrated,so that the proximal radiopaque marker 49 appears on the fluoroscope.Again, the single distal edge marker is still visible near the distalmargin, and the distal markers 46 are visible deeper in the posteriorcerebral artery, confirming that the distal region 21 is still properlylocated within the posterior cerebral artery.

As shown in FIG. 9 f, the surgeon has continued manipulating thebridging device with the delivery wire 43, pushing and pulling asnecessary to achieve the shape for the central region that best bridgesthe aneurysm neck.

As shown in FIG. 9 g, the surgeon has withdrawn delivery catheter 2proximally, to fully release the bridging device, including theradiopaque marker 55 which is fixed that the distal end of the tethers.Further manipulations may be necessary to ensure that the central regionstruts and V-shaped elements are best located over the aneurysm neck,the distal edge marker is still co-located with the distal edge of theneck, and the proximal radiopaque marker 49 is co-located with thedistal extent of the basilar artery. When the surgeon is satisfied withthe placement, he operates a power supply connected to the electrolyticdetachment joint 44 to sever the delivery wire 43 from the bridgingdevice. Although it will not be visible under current imagingtechniques, the bridging device is shown in this FIG. 9 g, to illustratea typical placement. After detachment from the delivery wire, thebridging device is lodged within the bifurcation, with the proximalregion expanded to engage the wall of the basilar artery, as shown inFIG. 9 g. While permanent implantation will usually be desired, thedevice may be used as a temporary scaffold to assist in placement of thecoils, and the method may be completed in such cases by leaving thedetachment joint 44 intact as shown in FIG. 10 while the bridging deviceis otherwise fully deployed while the occlusive device or substance inthe aneurysm is setting up, and thereafter withdrawing the bridgingdevice into the distal segment of delivery catheter and removing thebridging device from the bifurcation after delivering the occlusivedevice or substance.

To release the device and obtain the optimal shape of the protuberantcentral region 23, in the method illustrated in FIGS. 9 a through 10,the surgeon deforms (or re-forms) the bridging device in situ, typicallydeforming the device into a shape which is different from itsunrestrained unstressed, large diameter configuration illustrated inFIG. 6. To place and deform the bridging device, the surgeon deploys thedistal end of the bridging device from the distal end of the deliverycatheter as shown in FIG. 9 a. Upon deployment, the distal region of thebridging device self-expands and becomes lodged in the outlet artery.Lodgment in the outlet artery provides sufficient fixation such thatsubsequent manipulation, including pushing, pulling and twisting todeform the central region, is accomplished without holding the distalregion with any device associated with the delivery system, and withoutapplying proximally compressive force on the distal end or distal regionof the bridging device, and without squeezing the device or pulling thedistal region toward the proximal region. That is, no portion of thedelivery system or other device is used to restrain the distal region,or pull it proximally toward the proximal region, and lodgment withinthe outlet vessel is relied upon to hold the distal region in placewhile the proximal region and central region are pushed, pulled andtwisted by the surgeon implanting the device. Upon deployment of thecentral region, as illustrated in FIG. 9 c, the central region twists,or rotates about the longitudinal axis of the bridging device, relativeto the distal region (which is lodged in the outlet vessel). Release ofthe proximal region also causes the proximal region to rotate about thelongitudinal axis of the bridging device, relative to the central anddistal regions. Thus, twisting of the central region and proximalregion, relative the distal region, can be accomplished by releasing thecentral region and proximal region from the delivery catheter.

While pushing and pulling the device with the delivery wire tomanipulate the central region while the proximal region is still withinthe distal tip of the delivery catheter (FIG. 9 f), and while pushingand pulling the proximal device with the delivery wire after release ofthe proximal region from the delivery catheter (FIG. 9 g), the surgeonmay twist the proximal region, which causes opening of the spiral struts(proximal spiral struts 39, or distal spiral struts 42, or both) andfurther bulging of the central region. The surgeon continues to push,pull and twist the bridging device, using the delivery wire, until thecentral region is deformed such that the central region struts andV-shaped elements are best located over the aneurysm neck. Thus, thoughthe bridging device is fabricated to be self-expandable, and iselastically or pseudoelastically deformable to a small diameterconfiguration for delivery through a delivery catheter, and elasticallyor pseudoelastically deformable to expand and revert to, or toward, itsoriginal large diameter configuration when released from the deliverycatheter, it may also be further elastically or pseudoelasticallydeformed to enlarge or reduce the diameter of the central section, ordeform it non-uniformly to bulge toward the neck of the aneurysm.

FIG. 11 illustrates the step of filling the aneurysm sac with occlusivematerial, after placement of the bridging device. As illustrated, thedelivery catheter and delivery wire have been withdrawn, and anotherdelivery catheter 56 has been inserted through the vasculature, throughthe lumen defined by the proximal region 22, out of the device, throughspaces between the struts or segments of the central region 23, and intothe aneurysm 20. The surgeon will use this catheter to deliver occlusivematerial, which may include the illustrated embolic framing coil 57,embolic coils, hydrocoils, or embolic substances. After placement of theembolic material, the central struts and V-shaped elements whichprotrude from the main axis of the device (relative to the diameterestablished by the distal and proximal regions) will act as scaffolds tohold the embolic material (especially the finest embolic coil loops) inplace and prevent it from dropping out of the aneurysm sac to occludethe opposite posterior cerebral artery.

Though the method is illustrated with specific reference to the basilartip aneurysm, which occurs at the terminus of the basilar artery, themethod can be used to treat bifurcation aneurysms at bifurcations of themiddle cerebral artery 17, the internal carotid artery 5, the anteriorcommunicating artery 19 (at the anterior cerebral artery 16), thesuperior cerebellar artery, the pericallosal artery (a continuation ofthe anterior cerebral artery), the posterior inferior cerebellar artery,or any other bifurcation. Each bifurcation is characterized by an inletartery, and first outlet artery and a second outlet artery, which in theillustration of FIGS. 9 a through 9 g correspond to the basilar artery,the left posterior communicating artery and the right posteriorcommunicating artery.

The bridging device can be made various configurations in which thenumber of zigzag segments is varied, the length of the segments or thelength of the spiral struts is varied, or the number of V-shapedelements in the various zigzag segment is varied. These variousembodiments are described in the following figures. FIG. 12 illustratesan embodiment of a protuberant aneurysm bridging device 61 assembledover a mandrel 62. The device 61 comprises a distal end region 21,comprising a zigzag segment 63 d comprising V-shaped segments 64 d and aproximal end region 22 comprising a zigzag segment 63 p comprisingV-shaped segments 64 p, and a central region 23. The central regioncomprises two first intermediate spiral strut regions 65, eachcomprising a plurality of first intermediate spirally oriented struts66, two second intermediate zigzag segments 67 d and 67 p each with aplurality of second intermediate V-shaped struts 68, and a plurality ofspirally oriented center struts 69 joining vertices of the zigzagsegment of the second intermediate V-shaped struts on either end of thespirally oriented center struts. This protuberant aneurysm bridgingdevice can be symmetric about an axis running laterally to thelongitudinal axis. FIG. 13 illustrates a side view of the protuberantaneurysm bridging device 61 clarifying the end regions 63 d and 63 p,the central region 69, and first intermediate strut regions 65. Thespirally oriented struts that join each of the zigzag segments extend,as described in relation to the spirally oriented struts of FIGS. 3 and4, circumferentially around the volume defined by the device, from avertex of one zigzag segment to a vertex of the next zigzag segmentwhich is circumferentially displaced from the originating vertex. Thedisplacement may be one, two or three vertices or more (using a vertexof the zigzag segments as a unit of measure around the circumference ofthe device).

The protuberant aneurysm bridging device 61 is fabricated by cutting apattern. The pattern can be cut into a flat sheet of device materialwhich is then rolled and the ends affixed to each other. The flat sheetembodiment can be fabricated using laser cutting, electrical dischargemachining (EDM), wire EDM, photochemical etching, mechanically machined,or otherwise machined. In other embodiments, the device 61 can be cutfrom a tubular blank using methodology itemized above for the flat sheetembodiment.

The protuberant aneurysm bridging device 61 can be fabricated frommaterials such as nitinol, shape memory nitinol, martensitic nitinol,superelastic or pseudoelastic nitinol, stainless steel, titanium, cobaltnickel alloys, tantalum, and the like. The device 61 can be malleable orit can be elastically biased outward to be self-expanding.

Following machining, the protuberant aneurysm bridging device 61 can beexpanded or dilated from a first, smaller inside diameter, to a second,larger inside diameter. The device 61 can next be temporarily affixedabout the mandrel 62. The device 61 can next be selectively twisted toexpand and re-configure specific regions, especially the spiral regionssuch as the central region 69 or one or both of the first intermediateregions 65. The device 61 can next be heat set to retain its shape. Forexample, when made of superelastic nitinol, the device 61 is fabricatedfrom nitinol which can be heat set at temperatures of about 450° C. toabout 550° C. while maintained in a specific shape, after which thetemperature and restraint can be removed leaving the device in itsfinal, unstressed configuration. Optional quenching, such as with water,can be used to rapidly cool the device 61. The heat set time can rangefrom about 1 minute to about 15 minutes depending on mass, material, andtemperatures used. FIG. 12 illustrates one of many configurationspossible for a device using different flat patterns, differentmaterials, different numbers of struts, and different strut thicknesses,widths, and lengths. The number of struts can vary between about 6 andabout 16 or more, and preferably between about 8 and 14, with agenerally similar number of slots interspaced between the struts.

FIG. 14 illustrates a side view of the distal end of a protuberantaneurysm bridging device 70 comprising an end region 71, a firstintermediate region 72, a second intermediate region 73, and a centralregion 74. In this configuration the device 70 is generally the same orsimilar as that of the device 61 of FIG. 12.

FIG. 15 illustrates a side view of a protuberant aneurysm bridgingdevice 75 comprising two end regions 76, two first intermediate regions77, two second intermediate regions 78, and a central region 79.

Referring to FIG. 15, the two first intermediate regions 80 areconfigured to provide bending out of the longitudinal axis. The centralregion 81 is further configured for axial bending. The two end regions82 and the two second intermediate regions 83 comprise zigzag segments,maintain partial diamond, diamond, or wave structures that are generallystiff and resist bending out of the longitudinal axis but providesuperior hoop strength and holding power within an artery or vessel.Furthermore, the central region 79 is generally loosely configured withlarge spaces between struts or elements and permits blood flowtherethrough. The first intermediate regions 77 are further configuredfor greater open space than the end regions 76 or the secondintermediate regions 78. The first intermediate region 77 can bebeneficial when placed across a bifurcation or trifurcation outletvessel and permit continued blood flow without embolization. The endregions 76 can be configured, as illustrated, with an outward taper tofacilitate holding within the vessel wall.

FIG. 16 illustrates a flat pattern 84 corresponding to the tubularprotuberant aneurysm bridging device 61, 70 or 75. The flat pattern 84comprises a plurality of end bars 85, a plurality of first intermediatebars 86, a plurality of second intermediate bars 87, and a plurality ofcentral bars 88. In FIG. 16, the flat pattern 84 comprises a pluralityof repeating patterns, for example 10 repeat patterns in the lateraldirection, but this number can vary as described herein. The end regions85 are formed as undulations or “V” patterns interconnected to eachother. The end regions 85 can also be formed as a plurality ofapproximately diamond-shaped patterns. The end regions 85 areinterconnected at their interior ends to the outside ends of the firstintermediate region bars or struts 86. In the device of FIG. 16, theinner ends of the first intermediate struts 86 are connected to theouter ends of the second intermediate struts 87 but the connection isnot symmetrical but slightly off-center of the arc connecting the “V”patterns. The first intermediate struts are configured with a slightwave but can also be straight, more strongly “S” shaped, or shaped insome other suitable wave or geometric pattern. This flat pattern 84 canbe used to program a cutting system to create the pattern in a tubularblank. Alternately, this flat pattern 84 can be fabricated into a flatsheet of material which is then rolled circumferentially and the endswelded or otherwise affixed.

In the illustrated embodiment, a preferred specification provides forthree longitudinal cells and ten repeat patterns circumferentially. Thewidth of the bars is about 65 micrometers and the wall thickness of thematerial is about 74 micrometers. The illustrated flat pattern 84 can besuitable for, or cut from, a tube having a diameter of about 2.464 mm.The diameter of the tubing blank can vary depending on the application.The wall thickness can vary from about 0.25 mm to about 0.5 mm to about0.20 mm. The bar or strut width can vary from about 0.25 mm to about 0.1mm with a preferred range of about 0.3 mm to about 0.5 mm.

FIG. 17 illustrates a protuberant aneurysm bridging device 89 fabricatedfrom a flat pattern similar to, or the same as, that illustrated in FIG.16. The device 89 comprises two end sections 90, two first intermediatesections 91, two second intermediate sections 92, and a central section93. The wavy patterns in the end sections 90 are relatively large withlarge strut lengths. The overall length of the device 89 is about 15 mmbut this length can vary between about 8 mm and about 25 mm.

FIG. 18 illustrates a protuberant aneurysm bridging device 89 comprisingtwo end sections 94 and a central region comprising two firstintermediate sections 95, two second intermediate sections 96, and acentral spiral strut section 97. The wavy patterns in the end sections94 are relatively short and provide for a stiffer end section 94 than inthe end sections 90 of the device 89. The second intermediate sections96 are relatively long compared to the second intermediate sections 96of the device 89 of FIG. 17. These types of strut length changes aretypically performed at the stage of fabricating the flat pattern such asin FIG. 16. The overall length of the device 89 is about 15 mm but canrange from about 8 mm to about 25 mm. The central region 97 and the twosecondary intermediate regions 96 together comprise a length of about 10mm but this length can vary between about 5 mm and about 15 mm. Theoutside diameter of the two end sections is about 4 mm in FIG. 18 butthis diameter can vary between about 2 mm and about 6 mm. The diameterof the enlarged central region, at its greatest is about 8 mm but canvary between about 3 mm and about 12 mm.

FIG. 19 illustrates a side view of a protuberant aneurysm bridgingdevice 99 comprising two end sections 100 and a central regioncomprising two first intermediate sections 101, two second intermediatesections 102, and a central spiral strut section 103. The device 99comprises second intermediate regions 102 which have shorter struts thanthose 96 of device 89 and about the same as the intermediate regions 92of device 89. However the central region 103 is longer than the centralregion 97 of device 89 and about the same as the central region 93 ofdevice 89. The overall length of the protuberant aneurysm bridgingdevice 99 is about 15 mm but can vary between about 8 and 25 mm. Thecentral region 103 and the two secondary intermediate regions 102comprise about 8.5 mm length but this can vary between about 5 mm andabout 15 mm. The overall diameter of the unstressed, expanded centralregion 103 is about 6 mm but can vary between about 4 mm and about 12mm. The outside diameter of the end regions 100 is about 4 mm with arange of about 2 mm to about 8 mm.

FIG. 20 illustrates a flat pattern 104 of a protuberant aneurysmbridging device comprising 16 repeat patterns in the circumferentialdirection. The flat pattern 104 comprises two end regions 105 and acentral region comprising two first intermediate regions 106, twosecondary intermediate regions 107 and a central spiral strut region108. The flat pattern 104 is denser in the circumferential directionthan the flat pattern 84 since it has more struts. The flat pattern 104comprises three cells, wherein two cells comprise an end region 105 anda secondary intermediate region 107 as well as the connecting firstintermediate region 106. The third cell comprises the central region 108and the two secondary intermediate regions 107. The tube diameterpreferred for this configuration is about 2.462 mm on the outside butcan range from about 1 mm to about 4 mm. The wall thicknesses aresimilar to those specified for the flat pattern 84 in FIG. 16. The barwidths would generally be somewhat smaller for the embodiment 104 thanin the flat pattern 84 since there are more bars (and spaces) in flatpattern 104 than in flat pattern 84.

FIG. 21 illustrates a side view of a protuberant aneurysm bridgingdevice 109 fabricated from the flat pattern 104. The device 109comprises two end regions 110, one at each end. The device 109 furthercomprises a central region comprising two first intermediate sections111 and two second intermediate sections 112, on both sides of thecentral spiral strut section 113. All sections and struts are preferablyformed integrally, as is the case for most devices disclosed within thisdocument. The number of repeat patterns in FIG. 21 is 16 resulting in adevice 109 with a high metal to open space ratio relative to the devicesfabricated from the flat pattern in FIG. 16. The first intermediatesections 111 and the central section 113 comprise more open space thanthe rest of the device 109.

FIG. 22 illustrates a close-up of a protuberant aneurysm bridging device114, which is similar to the device 109 of FIG. 21. The device 114comprises the central region 115, the second intermediate region 116,the arcuate ends 117 of the second intermediate region 116, and theconnector region 118.

The connector region 118 is slightly thicker than the majority of thebar structure of the device 114. This increased thickness or bar widthin the connector region 118 provides additional stiffness and strengthin the connector region. The connector region 118 is affixed to thearcuate region 117 connecting the adjacent bars of the secondaryintermediate region 116.

FIG. 23 illustrates an oblique view of a protuberant aneurysm bridgingdevice 119 having eight repeat patterns in the circumferentialdirection. The device 119 comprises the first and second end regions120, and a central region comprising two first intermediate regions 121,two secondary intermediate regions 122, and a central spiral strutregion 123. The protuberant aneurysm bridging device 119 has more openspace ratio than devices having greater numbers of repeat patterns suchas shown in FIGS. 17, 18, and FIG. 21. The secondary intermediate region122 comprises relatively short strut lengths.

FIG. 24 illustrates a protuberant aneurysm bridging device 124 inoblique view comprising two end regions 125, two first intermediateregions 126 (with spiral struts), two secondary intermediate regions 127(zigzag segments) and a central region 128. This protuberant aneurysmbridging device 124 is similar to the device 119 of FIG. 23 except thatthe bars in the secondary intermediate region 127 are longer than thosein the secondary intermediate region 122 of FIG. 23. Both the device 124and the device 119 comprise eight bars and eight spaces movingcircumferentially in the central sections 123 and 128.

FIG. 25 a illustrates a cerebrovascular aneurysm 129 taken withfluoroscopy and dye injection wherein the aneurysm 129 is located at thejunction of a bifurcation comprising an inflow artery 130, a first exitartery 131, and a second outflow artery 132.

FIG. 25 b illustrates a cerebrovascular aneurysm 125 taken withfluoroscopy and dye injection wherein the aneurysm 129 is located at thejunction of a bifurcation comprising an inflow artery 130, a first exitartery 131, and a second outflow artery 132. A simplified example of acommercially available cerebrovascular stent 133 is illustrated placedwithin the bifurcation such that the inlet to the device 133 is coaxialwith the inlet artery 130 and the outlet of the device 133 is coaxialwith the first outlet artery 131. An embolizing mass, such as platinumcoils 134, is shown within the aneurysm 129.

The stent 133 is shown placed across the entrance to, or the neck of,the aneurysm 129 allowing the coil mass to occlude the entrance to thesecondary outlet artery 132.

FIG. 25 c illustrates a cerebrovascular aneurysm 129 taken withfluoroscopy and dye injection wherein the aneurysm 129 is located at thejunction of a bifurcation comprising an inflow artery 130, a first exitartery 131, and a second outflow artery 132. A simplified example of aprotuberant aneurysm bridging device 135 is illustrated placed withinthe bifurcation such that the inlet to the device 135 is coaxial withthe inlet artery 130 and the outlet of the device 135 is coaxial withthe first outlet artery 131. An embolizing platinum coil mass is shownwithin the aneurysm 129. The protuberant aneurysm bridging device 135 isshown placed across the entrance to, or the neck of, the aneurysm 129and protruding into the aneurysm neck holding, via the central bulge 136of the device and supporting the platinum coil mass 137 to allow flowinto the entrance to the secondary outlet artery 132. The bars of thedevice 135 are widely spaced in the region of the secondary outletartery 138 inlet as well as in the region of the aneurysm 129 neck suchthat blood is free to flow through these widely spaced device bars whileproviding some holding power to the embolizing coil mass 137.

FIG. 26 a illustrates a giant bifurcate cerebrovascular aneurysm 139 ata bifurcation with an entrance vessel 140 to the bifurcation, a firstoutflow vessel 141 and a second outlet vessel 142.

FIG. 26 b illustrates a giant bifurcate cerebrovascular aneurysm 139taken with fluoroscopy and dye injection wherein the aneurysm 139 islocated at the junction of a bifurcation comprising an inflow artery140, a first exit artery 141, and a second outflow artery 142. Asimplified example of a commercially available cerebrovascular stent 133is illustrated placed within the bifurcation such that the inlet to thedevice 133 is coaxial with the inlet artery 140 and the outlet of thedevice 133 is coaxial with the first outlet artery 141. An embolizingmass, such as platinum coils 134, is shown within the aneurysm 139. Thestent 133 is shown placed across the entrance to, or the neck of, theaneurysm 139 allowing the coil mass to occlude the entrance to thesecondary outlet artery 142.

FIG. 26 c illustrates a giant bifurcate cerebrovascular aneurysm 139taken with fluoroscopy and dye injection wherein the aneurysm 139 islocated at the junction of a bifurcation comprising an inflow artery140, a first exit artery 141, and a second outflow artery 142. Asimplified example of a protuberant aneurysm bridging device 135 isillustrated placed within the bifurcation such that the inlet to thedevice 135 is coaxial with the inlet artery 140 and the outlet of thedevice 135 is coaxial with the first outlet artery 141. An embolizingplatinum coil mass is shown within the aneurysm 139. The protuberantaneurysm bridging device 135 is shown placed across the entrance to, orthe neck of, the aneurysm 139 and protruding into the aneurysm neckholding, via the central bulge of the device 135 and supporting theplatinum coil mass 134 to allow flow into the entrance to the secondaryoutlet artery 142. The bars of the device 135 are widely spaced in theregion of the secondary outlet artery 142 inlet as well as in the regionof the aneurysm 139 neck such that blood is free to flow through thesewidely spaced device bars while providing some holding power to theembolizing coil mass 134.

FIG. 27 a illustrates a cerebrovascular aneurysm 143 taken withfluoroscopy and dye injection wherein the aneurysm is located at thejunction of a bifurcation comprising an inflow artery 144, a first exitartery 145, and a second outflow artery 146.

FIG. 27 b illustrates a cerebrovascular aneurysm 143 taken withfluoroscopy and dye injection wherein the aneurysm 143 is located at thejunction of a bifurcation comprising an inflow artery 144, a first exitartery 145, and a second outflow artery 146. A simplified example of acommercially available cerebrovascular stent 133 is illustrated placedwithin the bifurcation such that the inlet to the device 133 is coaxialwith the inlet artery 144 and the outlet of the device 133 is coaxialwith the first outlet artery 145. An embolizing mass, such as platinumcoils 134, is shown within the aneurysm 143. The stent 133 is shownplaced across the entrance to, or the neck of, the aneurysm 143 allowingthe coil mass to occlude the entrance to the secondary outlet artery146.

FIG. 27 c illustrates a cerebrovascular aneurysm 143 taken withfluoroscopy and dye injection wherein the aneurysm 143 is located at thejunction of a bifurcation comprising an inflow artery 144, a first exitartery 145, and a second outflow artery 146. A simplified example of aprotuberant aneurysm bridging device 135 is illustrated placed withinthe bifurcation such that the inlet to the device 135 is coaxial withthe inlet artery 144 and the outlet of the device 135 is coaxial withthe first outlet artery 145. An embolizing platinum coil mass is shownwithin the aneurysm 143. The protuberant aneurysm bridging device 135 isshown placed across the entrance to, or the neck of, the aneurysm 143and protruding into the aneurysm neck, and holding, via the centralbulge of the device 135, and supporting the platinum coil mass 134 toallow flow into the entrance to the secondary outlet artery 146. Thebars of the device 135 are widely spaced in the region of the secondaryoutlet artery 146 inlet as well as in the region of the aneurysm 143neck such that blood is free to flow through these widely spaced devicebars while providing some holding power to the embolizing coil mass 134.

FIG. 28 a illustrates a cerebrovascular aneurysm 147 taken withfluoroscopy and dye injection wherein the aneurysm 147 is located at thejunction of a bifurcation comprising an inflow artery 148, a first exitartery 149, and a second outflow artery 150.

FIG. 28 b illustrates a cerebrovascular aneurysm 147 taken withfluoroscopy and dye injection wherein the aneurysm 147 is located at thejunction of a bifurcation comprising an inflow artery 148, a first exitartery 149, and a second outflow artery 150. A simplified example of acommercially available cerebrovascular stent 133 is illustrated placedwithin the bifurcation such that the inlet to the device 133 is coaxialwith the inlet artery 148 and the outlet of the device 133 is coaxialwith the first outlet artery 149. An embolizing mass, such as platinumcoils 134, is shown within the aneurysm 147. The stent 133 is shownplaced across the entrance to, or the neck of, the aneurysm 147 allowingthe coil mass to occlude the entrance to the secondary outlet artery150.

FIG. 28 c illustrates a cerebrovascular aneurysm 147 taken withfluoroscopy and dye injection wherein the aneurysm 147 is located at thejunction of a bifurcation comprising an inflow artery 148, a first exitartery 149, and a second outflow artery 150. A simplified example of aprotuberant aneurysm bridging device 135 is illustrated placed withinthe bifurcation such that the inlet to the device 135 is coaxial withthe inlet artery 148 and the outlet of the device 135 is coaxial withthe first outlet artery 149. An embolizing platinum coil mass is shownwithin the aneurysm 147. The protuberant aneurysm bridging device 135 isshown placed across the entrance to, or the neck of, the aneurysm 147and protruding into the aneurysm neck, holding, via the central bulge ofthe device 135, and supporting the platinum coil mass 134 to allow flowinto the entrance to the secondary outlet artery 150. The bars of thedevice 135 are widely spaced in the region of the secondary outletartery 150 inlet as well as in the region of the aneurysm 147 neck suchthat blood is free to flow through these widely spaced device bars whileproviding some holding power to the embolizing coil mass 134.

Each of the protuberant aneurysm bridging device embodiments and becontrolled with the various methods used for devices and other devicesmade of nitinol. Nitinol is preferred because its biocompatibility iswell proven, and it is available in numerous compositions withwell-controlled, predictable transition temperatures. Other shape memoryor pseudoelastic materials can also be used, and normally elasticstainless steel, cobalt nickel alloys, and plastics may be used. Thenitinol used for the device may be used in its shape memory formulation,with a transition temperature just above body temperature, in which casethe device may be returned to its memorized shape upon the injection ofwarm water (just above body temperature). Alternatively, the nitinolused for the device may be used in its pseudoelastic formulations, inwhich the nitinol is superelastic (also called pseudoelastic) at bodytemperature, in which case the device will automatically revert to itsmemorized shape when inside the body. The superelastic device can bedeformed to fit within the delivery catheter so that it can be insertedinto the body, and it reverts to the memorized shape, utilizingelasticity, phase changes, or both, when released from the catheter inthe blood stream.

Common among the embodiments of the aneurysm occluding devices is thedesire that the occluding structure enhance formation of thrombus withinthe aneurysm. To enhance this function, the occluding structure may becoated with known thrombogenic materials such as platinum. The strutswhich remain outside the aneurysm sac and within the blood streampreferably remain uncoated with such a thrombogenic coating, and arepreferably coated with an anti-thrombogenic coating such as heparin,tin, or other such coatings as previously disclosed in the medicaldevice art. Thus the occluding device can comprise segments of varyingthrombo-active coatings, depending on the desired characteristic of eachsegment. The devices can also be coated with materials such as tantalum,gold and platinum in order to enhance the visibility of the devicesunder fluoroscopy. The devices can be clearly visualized underintravascular ultrasound which can be used to aid in deployment andproper placement. While the devices will provide for the primarytreatment of aneurysms, they may also be used in conjunction withembolic materials such as, but not limited to, baskets, embolic coils,hardenable polymers, and the like in order to hold these foreignmaterials within the aneurysm and prevent their migration from theaneurysm into the blood stream.

Certain aspects of the inventions include methods of implantation of theprotuberant aneurysm bridging device. In some embodiments of the method,the devices is loaded into a delivery microcatheter. Under anesthesiaand using standard hospital aseptic technique, a Seldinger technique canbe used to obtain percutaneous access to the femoral artery and anoptional introducer sheath can be retained within the arterial accesssite to aid in device insertion and removal. A guide catheter can berouted through the femoral access site to the cerebrovasculature, or asclose as possible, with the aid of a guidewire. The guidewire can beremoved and the device delivery microcatheter can be introduced throughthe guide catheter and advanced into the Basilar artery, the circle ofWillis, or other location. The device delivery microcatheter can beadvanced under fluoroscopic guidance, single or bi-planar, to the targetregion. The distal end of the device delivery microcatheter can beadvanced into the first outlet vessel of a bifurcation. The proximal endof the device delivery microcatheter can be retained well within theinlet vessel to the bifurcation. The radiopaque markers can be alignedat this time to ensure the device deploys with the open mesh directedtoward the entrance to the second exit vessel. The protuberant aneurysmbridging device can be expanded using an angioplasty type balloon orusing internal recovery such as spring biasing, shape memorytransformation, or the like. The position of the protuberant aneurysmbridging device can be confirmed using fluoroscopy, IVUS, MRI, or thelike. Further expansion of the protuberant aneurysm bridging device canbe performed, if necessary, prior to final detachment of the device fromthe delivery catheter and removal of the device delivery catheter fromthe patient.

Following placement of the device, a microcatheter can be used todelivery embolic devices into the aneurysm through the open walls of thecentral region of the device. When the procedure is completed and fullyinterrogated to ensure correct treatment (e.g. no embolic coilsprotruding into the parent vessel), the embolic device delivery devicescan be removed from the patient.

While the preferred embodiments of the devices and methods have beendescribed in reference to the environment in which they were developed,they are merely illustrative of the principles of the inventions. Theelements of the various embodiments may be incorporated into each of theother species to obtain the benefits of those elements in combinationwith such other species, and the various beneficial features may beemployed in embodiments alone or in combination with each other. Otherembodiments and configurations may be devised without departing from thespirit of the inventions and the scope of the appended claims.

We claim:
 1. A method of placing an aneurysm bridging device in theneurovasculature of a patient, said method comprising the steps of:placing the aneurysm bridging device within the neurovasculature of apatient; securing the distal end of the aneurysm bridging device withinthe neurovasculature; manipulating the proximal end of the aneurysmbridging device to deform a central region of the endoluminal support,where said manipulating comprises pushing, pulling and twisting theproximal end of the aneurysm bridging device, while the distal end ofthe aneurysm bridging device is secured within the neurovasculature;securing the proximal end of the aneurysm bridging device within theneurovasculature to maintain the central region of the aneurysm bridgingdevice in a deformed state.
 2. A method of claim 1, wherein the pushing,pulling, and twisting of the proximal end is accomplished withoutapplying proximally compressive force on the distal region of thebridging device.
 3. A method of treating a wide-necked aneurysmproximate a bifurcation in the neurovasculature of a patient, saidbifurcation characterized by an inlet vessel providing blood flow to afirst outlet vessel and a second outlet vessel, said method comprising:providing a bridging device for bridging the aneurysm, said bridgingdevice comprising an inlet anchoring portion at a first end of thebridging device and an outlet anchoring portion at a second end of thebridging device, and one or more struts extending from the inletanchoring portion to the outlet anchoring portion and protrudingarcuately and outwardly from a center portion of the bridging device;installing the bridging device in the neurovasculature of the patient,proximate the aneurysm, such that the inlet anchoring portion isdisposed within the inlet vessel and the outlet anchoring portion isdisposed within the first outlet vessel, and the struts protrude towardthe aneurysm and the second outlet vessel; deforming the bridging deviceby securing the outlet anchoring portion within the outlet vessel, andpushing and twisting the inlet anchoring portion relative to the outletanchoring portion, without applying proximally compressive force on theoutlet anchoring portion; and implanting an embolizing mass into theaneurysm, such that the struts of the bridging device retain theembolizing mass within the wide-necked aneurysm and maintain a flow pathfrom the inlet vessel to the second outlet vessel which is substantiallyun-occluded by the embolizing mass.
 4. The method of claim 3, whereinaneurysm is a wide-necked basilar tip aneurysm, the inlet vessel is thebasilar artery, the first outlet vessel is a first posterior cerebralartery, and the second outlet vessel is a second posterior cerebralartery.
 5. The method of claim 3, wherein the bifurcation is abifurcation of a middle cerebral artery, an internal carotid artery, theanterior communicating artery, a superior cerebellar artery, apericallosal artery, the basilar artery or a posterior inferiorcerebellar artery.
 6. A method of treating a wide-necked aneurysm in theneurovasculature of a patient, at a bifurcation of a parent artery intoa first and second branch artery, said wide-necked aneurysmcharacterized by a neck opening into the bifurcation, said methodcomprising: providing a bridging device in a first catheter anddelivering said bridging device to the neck of the aneurysm; saidbridging device comprising a wire frame structure characterized by adistal region, a proximal region, and a bridging region disposed betweenthe distal region and the proximal region, said bridging device beingself-expandable from a small diameter configuration and a large diameterconfiguration; placing a distal segment of a first catheter across theneck of the aneurysm; deploying the distal region of the bridging devicefrom the distal segment of the first catheter while maintaining thebridging device in secure connection to a delivery wire, such that thedistal region expands to engage the wall of the first branch arterythereby fixing the distal region within the first branch artery;adjusting the position of the bridging device, so that a proximal edgeof the distal region is aligned with the junction of the aneurysm neckand the first branch artery; and thereafter deploying a bridging regionof the bridging device from the distal segment of the catheter, andcausing the bridging region to self-expand toward the large diameterconfiguration, so that the bridging region is disposed adjacent theaneurysm neck, spanning the aneurysm neck; deforming the bridging regionby pushing the proximal region of the bridging device and causing theproximal region to twist relative to the distal region, without applyingproximally compressive force on the distal region, to force the bridgingregion to assume a deformed configuration proximate the aneurysm neck;removing the proximal region from the distal segment of the catheter sothat the proximal region is disposed within the parent artery; anddelivering an occlusive device or substance from a second catheter intothe aneurysm sac.
 7. The method of claim 6 further comprising the stepof: detaching the bridging device from the first catheter and removingthe first catheter from the bifurcation, leaving the bridging devicewithin the bifurcation, spanning the neck of the aneurysm.
 8. The methodof claim 6 further comprising the steps of: withdrawing the bridgingdevice into the distal segment of the first catheter and removing thebridging device from the bifurcation after delivering the occlusivedevice or substance.
 9. A method of treating a wide-necked aneurysm inthe neurovasculature of a patient, at a bifurcation of a parent arteryinto a first and second branch artery, said wide-necked aneurysmcharacterized by a neck opening into the bifurcation, said methodcomprising: providing a bridging device in a first catheter anddelivering said bridging device to the neck of the aneurysm; saidbridging device comprising a wire frame structure characterized by adistal region, a proximal region, and a bridging region disposed betweenthe distal region and the proximal region, said bridging device beingself-expandable from a small diameter configuration and a large diameterconfiguration; placing the distal region of first catheter across theneck of the aneurysm; deploying the distal region of the bridging devicefrom the distal segment of the first catheter while maintaining thebridging device in secure connection to a delivery wire, such that thedistal region expands to engage the wall of the first branch arterythereby fixing the distal region within the first branch artery;adjusting the position of the bridging device, so that a proximal edgeof the distal region is aligned with the junction of the aneurysm neckand the first branch artery; and thereafter deploying the bridgingregion of the bridging device from the distal segment of the catheter,causing the bridging region to self-expand toward the large diameterconfiguration, so that the bridging region is disposed adjacent theaneurysm neck, spanning the aneurysm neck; deforming the bridging regionby pushing the proximal region of the bridging device and twisting theproximal region relative to the distal region, without applyingproximally compressive force on the distal region, to force the bridgingregion to assume a deformed configuration proximate the aneurysm neck;and thereafter removing the proximal region from the distal segment ofthe catheter so that the proximal segment is disposed within the parentartery; delivering an occlusive device or substance from a secondcatheter into the aneurysm sac.
 10. The method of claim 9 furthercomprising the step of: detaching the bridging device from the firstcatheter and removing the first catheter from the bifurcation, leavingthe bridging device within the bifurcation, spanning the neck of theaneurysm.
 11. The method of claim 9 further comprising the steps ofwithdrawing the bridging device into the distal segment of the firstcatheter and removing the bridging device from the bifurcation afterdelivering the occlusive device or substance.
 12. The method of claim 1,wherein the aneurysm bridging device comprises a pseudoelastic orelastic material, and is characterized by a small diameter configurationfor delivery through a delivery catheter, and a large diameterconfiguration to which can self-expands when released from a deliverycatheter, said method further comprising the steps of releasing theaneurysm bridging device from the delivery catheter to cause theaneurysm bridging device to self-expand toward the larger diameterconfiguration, in addition to manipulation the proximal end of theaneurysm bridging device to deform the central region.
 13. The method ofclaim 3, further comprising the steps of: providing the bridging devicein the form of a pseudo-elastic or elastic bridging device, saidbridging device being self-expandable from a small diameterconfiguration to a large diameter configuration, wherein, in the largediameter configuration, the bridging region has a larger diameter thanthe distal region and the proximal region; releasing the bridging devicefrom the delivery catheter to cause the aneurysm bridging device toself-expand toward the large diameter configuration, in addition todeforming the bridging device by pushing and twisting the inletanchoring portion relative to the outlet anchoring portion.